A Brominating and Hydroxylating Peroxidase from the Red Alga Cystoclonium purpureum

A particulate enzyme displaying peroxidase activity has been extracted from the red alga Cystoclonium purpureum (Huds.) Batt. The enzyme preparation was shown to contain ferri-protoporphyrin IX through its formation of formic acid hemochromogen with absorption maxima at 399, 402, 555 and 600 nm. The preparation catalyses the formation of 3-bromo-p-hydroxybenzyl alcohol from p-hydroxybenzyl alcohol in the presence of H₂O₂ and NaBr at pH = 5.4. The formation of 3-bromo-p-hydroxybenzyl alcohol was measured by gas chromato-graphy-mass spectrometry. At pH = 6.7, 4,5-di-hydroxybenzyl alcohol was formed. Addition of homogentisic acid stimulated the formation of dihydroxybenzyl alcohol and suppressed the brominating reaction. Iodide inhibits the enzyme. The results are consistent with a two-site model of the enzyme.